In construction sites and mining sites, routes on which haulage vehicles such as dump trucks often travel are unpaved, so that the road surface of such routes are getting rough as a result of frequent travel of the haulage vehicles.
Accordingly, a maintenance system for road maintenance in mines is known (for instance, Patent Literature 1).
Further, in order to perform maintenance of such mine roads, a method in which the suspension pressure of a traveling haulage vehicle is measured to determine the roughness of the road surface is also suggested (see, for instance, Non-Patent Literature 1).